【正文】 ath Anxiety ? RR 40/min, Cyanosis ? ABG: PaO2 61mm Hg(FiO2 ) PaCO2 35 mmHg, pH ? Xray: clouded glass ? Diagnosis： ARDS Acidosis 3 Intubation via mouth tracheotomy Monitoring and ventilation 4 Contents 0f outline ? Definition ? Etiology amp。1 Respiratory failure Guo Yubiao, amp。 Pulmonary amp。 Pathogenesis ? Classification ? Clinical manifestations ? Diagnosis ? Treatment 5 Introduction ? Be a frequently encountered medical problem ? A major cause of death in China ? Mortality from COPD, which ends in death from respiratory failure, continues to increase ? More than 70% of patients with pneumonia are attributed to respiratory failure ? About 1/3 patients in ICU in the United States, about 500 000 persons, receive mechanical ventilation each year 6 Introduction (cont.) ? Shortterm survival is more than 80% for acute respiratory failure not preceded by additional lung disease or systemic illness ? Multisystem an failure or preexisting renal, liver, or chronic gastrointestinal disease with malnutrition substantially worsens outlook ? About 17% of patients placed on mechanical ventilation require assistance for more than 14 days ? Among those requiring this amount of mechanical ventilation, elderly patients have a 9% survival and younger patients a 36% survival 7 Definition ? Be a clinical syndrome of respiratory and metabolism dysfunction caused by any condition that severely affects the lung’s ability to maintain arterial oxygenation or carbon dioxide elimination. ? Both acute or chronic respiratory failure may be divided into two main categories. ? A failure of gas exchange – hypoxemia ? A failure of ventilation – hypercapnia 8 Classification ? According to pathophysiology and arterial blood gas analysis: ? Type I: A failure of gas exchange Hypoxemia, PaO2 60 mmHg ? Type II: A failure of ventilation PaO2 60 mmHg, PaCO2 50 mmHg ? PaO2 60 mmHg, PaCO2 50 mmHg Iatrogenic 9 Classification ? According to the involved site ? Central respiratory failure ? Change of respiratory rhythm and frequency ? Peripheral respiratory failure ? Dyspnea ? According to onset of respiratory failure ? Acute, develops in seconds or hours ? Chronic, develops in days or longer, elevated HCO3 ? Acute onset of Chronic respiratory failure ? Have no definitive borderline ? According to mechanisms ? Pump failure ? Lung failure 10 Etiology ? Airway obstruction ? Airway inflammation, tumor, foreign bodies, fibrosis scar COPD and asthma ? Alveolar or interstitial lung diseases ? pneumonia, emphysema, pulmonary tuberculosis, diffuse interstitial pulmonary fibrosis, pulmonary edema ? Pulmonary vascular diseases ? Pulmonary embolism, pulmonary vasculitis ? Chest wall or pleural diseases ? Flail chest caused by trauma, pneumothorax, severe spinal deformity, massive pleural effusion ? Neuromuscular diseases ? Cerebrovascular diseases, craniocerebral trauma, cerebritis and sedativehypnotic, poliomyelitis, polyneuritis, myasthenia gravis 11 Respiratory Pump Failure（泵衰竭） ? Pump failure is caused by dysfunction of respiratory pump ? Low respiratory drive due to central or peripheral nervous system diseases, neuromuscular junction problem or fatigue of respiratory muscles→hypoventilation ? manifested as type Ⅱ respiratory failure 12 Lung Failure（肺衰竭） ? Lung failure is caused by disorder of lung parenchyma, pulmonary vascular or airway obstruction ? Airway obstruction → hypoventilation， manifested as type Ⅱ respiratory failure ? Disorder of lung parenchyma → dysfunction of oxygenation, manifested as hypoxemia ? Disorder of pulmonary vascular system → ventilation/perfusion mismatch, manifested as hypoxemia 13 Mechanisms amp。 PaO2 ↓ ? Hypoventilation ? VA = VE – VD ? The diffusion capacity of CO2 is 20 times of that of O2 25 20 15 10 5 肺泡分壓(kPa) 0 2 4 6 8 10 肺泡通氣量 (l/min) PACO2 PAO2 PACO2 =*VCO2/VA 16 Mechanisms of hypoxemia –– Diffusion abn